TRKH AND ITS HOMOLOG, TRKG, DETERMINE THE SPECIFICITY AND KINETICS OF CATION-TRANSPORT BY THE TRK SYSTEM OF ESCHERICHIA-COLI
Autor(en): | SCHLOSSER, A MELDORF, M STUMPE, S BAKKER, EP EPSTEIN, W |
Stichwörter: | BACTERIOPHAGE-T7 RNA-POLYMERASE; EXPRESSION; GENETIC-ANALYSIS; MEMBRANE-PROTEIN; Microbiology; NUCLEOTIDE-SEQUENCE; POTASSIUM UPTAKE | Erscheinungsdatum: | 1995 | Herausgeber: | AMER SOC MICROBIOLOGY | Journal: | JOURNAL OF BACTERIOLOGY | Volumen: | 177 | Ausgabe: | 7 | Startseite: | 1908 | Seitenende: | 1910 | Zusammenfassung: | The corrected sequence of the trkH gene of Escherichia coli predicts that the TrkH protein is a hydrophobic membrane protein of 483 amino acid residues, of which 41% are identical to those of the homologous and functionally analogous TrkG protein. These two proteins form the transmembrane component of the Trk system for the uptake of K+. Each protein alone is sufficient for high-level Trk activity. When Trk is assembled with the TrkG protein, Rb+ and K+ are transported with a K-m near or below 1 mM; however, the V-max for Rb+ is only about 7% of that for K+. When Trk is formed with TrkH, the affinities for both for K+ and Rb+ are somewhat lower, and the V-max for Rb+ is only 1% of that for K+ transport. The kinetics of transport in strains with wild-type alleles at trkG and at trkH suggest that both products participate in transport. |
ISSN: | 00219193 | DOI: | 10.1128/jb.177.7.1908-1910.1995 |
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geprüft am 19.05.2024